The present invention relates to a staking nut, and more particularly, to a cable grounding clamp having the staking nuts captive thereon for achieving the clamping function.
Grounding clamps for cables, such as coaxial cables on wireless telephone communication towers, have been employed in the past to ground the cables to protect against damage from lightning strikes. In use the outermost insulative jacket of the coaxial cable to be grounded is stripped where the clamp is to be applied. This will expose a conductive sheath of the cable beneath the jacket. A conductive copper strap is bent around the conductive sheath, and the strap is then clamped around the conductive sheath by applying individual lock washers over threaded rivet studs and threading conventional nuts on the studs to tighten the strap clamp in electrically conductive relationship to the coaxial cable sheath. In turn, the threaded rivet studs also act to rivet the lug of the grounding conductor to the strap clamp.
Such prior grounding clamps suffer several disadvantages. One disadvantage is the difficulty of installation due to the number of distinct individual pieces that must be manipulated to complete the clamping procedure. This is particularly a problem in such grounding clamps when it is considered that they are applied to coaxial cables at considerable altitudes above the ground by personnel who are suspended at that altitude during the application of the grounding clamps. Due to the multiple individual parts and the small size of some of their components such as the nuts and lock washers, the possibility exists that while the nuts are tightened, the nuts and lock washers may be dropped and lost.
The present invention overcomes these disadvantages in a simple and inexpensive manner. In the present invention the nuts which are utilized to achieve the clamping function are captive to the strap itself, but still capable of rotation relative to the fixed threaded studs or rivets to complete the clamping function. Moreover, the need for lock washers is obviated. Because the nuts are captive to the strap, they are easier to handle during installation and not subject to being dropped and lost during that procedure.
In one principal aspect of the present invention, a staking nut comprises a block portion having a face, and at least one surface adapted to be engaged by a tool to rotate the block portion. A passage extends into the block portion from the face, and the passage is threaded to receive a threaded stud therein. A substantially cylindrical staking shaft is on the block portion and extends from the face. The staking shaft has a given external cross-sectional dimension and also includes a passage which is coaxial with the passage of the block portion, with the staking shaft passage having a minimum cross-sectional dimension which is at least as large as the maximum cross-sectional dimension of the passage in the block portion. The staking shaft is formed of a material which is capable of expansion to an external cross-sectional dimension which is greater than the given external cross-sectional dimension.
In another principal aspect of the present invention, the block portion and staking shaft are formed in integral one piece relationship to each other.
In still another principal aspect of the present invention, the block portion and staking shaft are formed of the same material.
In still another principal aspect of the present invention, the material of the staking shaft is deformable to produce the expansion.
In still another principal aspect of the present invention, a grounding clamp comprises a flexible elongate metal strap having first and second ends; an elongate threaded stud at the first end of the strap; and a nut at the second end of the strap. The nut has a threaded passage therein aligned to threadedly receive the threaded stud into the threaded passage of the nut to attach the first and second ends together. A coupling couples the nut to the second end of the strap to prevent removal of the nut from the second end of the strap, but permit rotation of the nut relative to the stud while the nut is coupled to the second end to thread the nut onto the threaded stud.
In still another principal aspect of the present invention, the stud is non-rotatably fixed to the first end of the strap.
In still another principal aspect of the present invention, the aforementioned grounding clamp includes a conductor with a lug thereon, and the stud comprises a rivet which mounts the lug to the first end of the strap.
In still another principal aspect of the present invention, the strap has at least one opening through the strap adjacent the second end, and the nut and coupling comprise the aforementioned staking nut which is captive in the opening.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.